Application.internetReachability isn't enough for you?Internet Reachability Verifier is for making sure that the internet can be truly reached.
This is done with a technique called "captive portal detection", which is used by operating systems e.g. to determine if they should present a network login screen.

Several methods for the captive portal detection are available, modeled after the way how large platform-holder companies implement it (such as Google, Microsoft, Apple and Ubuntu). You also have an option to use a custom way based on your own web hosting.

If internet connectivity stops working middle of your own networking and you get error codes from some networking library, you can ask for reverification of the internet reachability (this asset will not actively monitor loss of effective networking, as that would use up user's mobile data quota unnecessarily).